(Reuters) – A six-passenger spaceship owned by an offshoot of Virgin Group fired its rocket engine in flight for the first time on Monday, a key step toward the start of commercial service in about a year, Virgin owner Richard Branson said.

“It was stunning,” Branson told Reuters. “You could see it very, very clearly. Putting the rocket and the spaceship together and seeing it perform safely, it was a critical day.”

The spaceship and its carrier aircraft, WhiteKnightTwo, took off from the Mojave Air and Space Port at 7 a.m. PDT (10.00 a.m. EDT), heading to an altitude of about 46,000 feet, where SpaceShipTwo was released.